Aerosol generator



Jan. 22, 1957 Filed Aug. 24, 1953 J. D; LEAR AEROSOL GENERATOR 3 Sheets-Sheet 1 Jan. 22, 1957 J. D. LEAR AEROSOL GENERATOR 3 Sheets-Sheet 2 Filed Aug. 24, 1953 I WW 5 INVENTOR.

. JosephD Lear, BY flzf/di ATTORNEY Jan. 22, 1957 D. LEAR AEROSOL GENERATOR Fi led Aug. 24, 1955 3 Sheets-Sheet 3 INVENTOR.

' Jcweph D. Lear,

AT TORNEY.

United States Patent AEROSOL GENERATOR- Joseph,D. Lear, Silver Creek, N. :Y.., assignor-toSilver- Creek Precision Corporation Silver Creek, N. .Y.

ApplicationAugust M,1953;Serial No. 375,964 l il w-v @(C ;2. 9.-..63);

' This ,invention relatesto aerosolgenerators, andgit has particular reference to a generator which is light v in weight, durable, easy to assemble,-an d capable-,of-;devel-. p n extremely n s s r: r p e J uid-tnartnl which "may beair borne .forconsiderable distances.

It has heretofore been proposed to ,disperse insecticide-s, fungicides, disinfectants, and the 1ike,- by centrifugally discharging solutions theneof from revolving, discs into; the path of an .ainstream, therebyatomizingflhe liquid; into a fine spray wherein ,the particles ;are of.-the order of fifty microns or less in diameter,and hence.are sufficiently small and light to be carried by the air-into; con t act;with

remotely, located crops, vegetation, or 7 other: surfaces for which ts fi cat nti ndica d a e articles z is desirable, not only, to project \the aerosol some distance from the generator, -but also toapply,itheparticlesdin a uniform thin fiimswithout; oyerdosage. Apparatusintende d ,f0 r,such purposes has taken theforrn'of a rnotoiy driven centrifugal pump supplied front-a liquid; reservoir, wherein ,the pump rotor is formed ofdises haying anextremely .thinperipheral discharge opening,;in conjunction with an air fan, also ,driven by -the motor, foreblowing air through a shroud or casin g garound theperiphery, of i i the pump,

The. present inyentionrelates toan improved generator of the type j1,1st de scrihed, the novel and advantageops features of whichwill ,be ,set forth in, the following; des r p i n, f re c e a ade; o e. mpanyin drawings, wherein:

Fig. 1 is a sideelevation of,th,e generator, when-positioned ,to discharge. the, aerosol. :With a relatively fiat traj-ectory;

' Fig, :2 is,als o a side elevation, with thegenerator set o ischarg a ahi h an -t a e o y;

Fig. 3 "is a frontelevationon ,an,enlarged scale;

Fig. 4 is a perspective, of, the adjuetablesupporting standard; i

Fig, 5 is an axial section through,tthe generatorcasing, with internal parts shownin eleyation;

Fig. 6, ,is additionally.,enlarged fragmentary ,section through thereservoirand fan end of the generator, showingals o an improvedshaft coupling and liquid seal;

Fig.- 7 is an ,enlarged fragmentary section through the pump; end of theicasing;

Fig. 8 is-a section on the line\88'of,F ig.-7;

Fig. 9 is a fragmentary:sectimrthrough:;the periphery of the pump, showing means. to render the-pump self priming; and

Fig, 1.0 is a, fragmentary section .on the line 10-40 of Fig. 3, showing:atbuilt intswitchland connectionbox.

The generator of the present invention comprises-three shell or casing sections, which are interfit-tedtoprovide a; generally cylindrical elongated body. These include a motor and fan casing 2l -having an end wall '22 formed with a concentric opening 23 (see Fig. 6) which fits lightly into at central adapter section '24 having an apertured end wall .25. The section Zqiv is -for med with a 2,773,679 Patented Jan. 22, 1957 shoulder 26 :adjacent the end wall 25, andthe reduced portion (of vthe-section 24-fits snuglyinto the third or reser- .metal, may be readily assembled to containall of the .elementsrequired for the complete machine.

Referringalso-to Figs. 5, 7, and S, the motorcasing section 21 has mountedtherein anelectric ir-rotorv 31,

' 'which-includesa main cylindrical frame 32 formed with spaced radial ribs 33'having bearing engagement with the internal wall of the-easing .21, thereby supporting the motor concentrically with the casing. The motor 31 is also provided witha front end 7 bell-34 containing a shaft bearing 35, and thebell is secured to the main frame 32 by bolts 36. One of theribs 33a, here shown as the rib at the 300. or eight ;oclock.. position in Fig. 8, is somewhat wider than the other ribs, and it is cut away or cored between its ends, as shown in Fig. 10, to provide an elongated-pocketor-switch box 37, communicating Withthe interior oftheframe 32. The casingsection 23 is also cut away at the area overlying the box 37, and the openingiscovered by a-cap plate 38, detachably secured by screws Sl -39a The plate38 provides a support for a control-switchfil-gand theend of a current snpplycable 42, andthere isadequate spacein the box 37 for wire junctions43, bymeans ofv wh-ich electricity is supplied ,to

vthernotor 31.

The'provision of,this switch box simplifies the assembly of the motor in its frame, and'facilitates,inaking the ,necessary connections without having excessive, lengths of wire whichare-frequently -a-;nuisance to stow away, and which often aret broken .due to interference with other parts It maybe noted in passing that the motor herein contemplated is a high speed- (16,000 R. P. M.) universal D. C.A. C. type, and hence no further description of through-the; section 24,-;as oneendof the cap 38 overlaps the telescopedwportions of the shells 2.1 and 24; Other screws, such as that designated bythe reference numeral 45 in; ,-Fig. 5 ,1 which are in circumferential alignment with the.screw Ema-also"passpthroughboth casing sections to enter tapped holes=in alternate ribs 33, By removing these;-SQEWs, the section 21 and its contents may be withdrawn-from theassemblywithwt disturbing the wiring in the box 37. Thegscrewafi shown in.Fig. 5 also serves to retain a, carrying handle 46 of any appropriate shape.

The shaft 51 ref the motor 31 is formed with an axial bore 52 thro.ughout,its length; The outer or left hand end of the shaftis provided with an annular collar 53,

which constitutes abacking forv a centrifugal pump impeller disc-54. As-shown,. the disc 54 is substantially saucer shape, havingafiat or normal portion 55 which abuts-thecollar 53,;and a tapering or conical portion 56 .extendingtherefrom to its periphery. The disc 5'4 is,

of course, concentricallypierced to fit over the shaft 51, and leakage at this joint is prevented by an O-ring seal 57. A complementary impeller disc 58, having the same shapeand size-as the disc 54, is also mounted on the shaft-51, the,concave sides of the discs facing toward each other. The discs are spaced internally by a cup shaped collar ,59, and they aI'eTretained in positionby :a

Washer 61 containing a sealing ring 62, and a nut 63 threaded onto the end of the shaft 51.

The shaft 51 is formed with a radial duct 64 in the space between the discs and 53, to discharge liquid into the cavity of the collar 59. The collar, in turn, is formed with a series of circumferentially aligned ducts 65 around its rim, so that liquid flowing through the bore 52 may find its way out between the discs 54- and 53, and thence to the periphery of the pump. The ducts 64 and 65 are of relatively small diameter, and of the order of a few hundzedths or tenths of an it h, in order to assist in breaking up the emergent liquid into a fine spray.

Referring particularly to Figs. 8 and 9, it will be noted that the periphery cf one of the discs or 56 (here the disc but not necessarily so) has been punched at three equally spaced arcs to form small dimples 65, which serve to space the discs slightly at their perirn ers. This is contrary to the teachings of the prior art, which proposed that discs of this character should close against each other resiliently when the pump was not in motion, and open slightly under centrifugal force when revolving. it had been thought that by so provicing a minute selfclosing discharge gap, liner particle size would be obtained, and it is true that such prior machines were, and are, capable of generating aerosols of very fine particle size.

iowever, there would frequently be occurrences when, upon bringing the pump up to its intended high speed, n aerosol would be formed, the liquid being unable to escape between the discs. it has now been discovered that this undesired result did not, as was naturally suspeered, follow from a mlsfitting of the discs, or squeezing them too ti htly together. it now appears, on the best evidence available, that air entrapped in the liquid, or between the discs, formed barrier layer at the periphery of the impeller, which, despite some compressive force upon it, precluded the flow of liquid. The dimples 66, which have an elevation of only a few thousandths of an inch, permit this air to escape readily, thus permitting free liquid flow, and rendering the pump self-priming under all conditions of operation. Equally line and uniform particle size is also attained.

Attention is now invited to Figs. and 6, for a discussion of the adapter reservoir sections 24 and 27. The section 27 is formed with a filling opening 71, normally closed by conventional bayonet joint cap '72. The end wall 3 is centrally pierced to receive a valve body 7 5-, which is soldered or welded to retain it in place and provide a l uid tight joint. The body "74 is axially bored and con erbored to receive a valve stem 75 adapted to abut a valve seat 76 in the body '74-. The stem 75 is formed with a reduced portion "F7 adapted to receive a sealing ring '73, with threaded portion 79 engageable in a companion thread in the valve body. An operating knob 31 is secured to the outer end or" the stem 5, its rotation is limited by a stop pin 82. riding in a slot in the knob 81. it will be obvious that the valve :3 be moved from fully closed to maximum open wor g positions by rotating the knob $1, and the degree or opening may be indicated by suitable marks on an index plate 84 secured on the wall '73.

A tube 85, secured in a radial hole in the valve body 74 on the inlet side of the seat '75, extends downwardly into the casing 2?, to provide means to supply liquid to the valve and pump. hole in the wall of the adapter section. 24, seats in the end of the valve body 74, and it communicates with the adjacent end of the shaft bore 52 through a sealing coupling 7, located in the adapter section 24.

l-leretofcre, great difiiculty has been experienced in providing a. reliable connection between the fixed outlet from the reservoir, and the inlet end of the hollow shaft leading to the impeller. Expensive constructions of seals were adopted in order to prevent leakage, and even this expedient was inadequate in service to eliminate many A suction tube 36, sealed in the premature failures. The coupling 87, which is comparatively inexpensive, has been found to provide an excellent leak proof connection between the fixed and rotary members, and to have a long service life.

The coupling 87 comprises a cylindrical sleeve 83, having a sealing element 89 tightly fitted in one end. The element 89 comprises a metallic cup 91 having a disc 92 of resilient material, such as a Buna type synthetic rubber, pressed therein, and the rubber is distended by means of a coil spring 93 embedded therein. A closure plate 94 retains the rubber from axial movement, and. the rim of the cup 91 is spun over the plate 94 to retain it in place. The cup, rubber, and plate are, of course, centrally apertured, so that the element 89 may be pressed over the end of the shaft 51, to provide a leakproof joint. A lubricant, such as molybdenum disulphide, may be worked into the joint between the shaft and the rubber.

The opposite end of the cylinder 38 receives a cylindrical gasket 95, also of oil resistant material, formed with annular grooves on the ends, and with a central aperture which may be hand pressed over the end of the suction tube 86. in operation, the motor shaft rotates in the element 3'5, and the sleeve 83 and gasket 95 are relatively stationary. The utility of the coupling 87 resides in the circumstance that it is practically impossible, particularly in mass production manufacture, and where sheet metal parts are involved, to bring the shaft 51 into exact alignment with the end of the tube 86. A radial displacement in excess of one thousandth of an inch is sufiicient to destroy other types of seals between rotating and fixed members. With the present seal, any unavoidable small radial or angular misalignment is compensated by a slight adjustment which is absorbed in the gasket 95, and the joint is thereby maintained liquidtight.

The shaft 51, adjacent the coupling 8'7, has mounted thereon a fan 191, to induce a fiow of air through the openings 28 and the aperture 23, and propel the air between the ribs 33 of the motor frame 32, and thence through the narrow annular orifice between the end of the casing 21 and the peripheries of the impeller discs 54 and 53. In operation, the pump acts as a centrifugal pump, drawing liquid from the reservoir casing 27, through the hollow shaft 51, and expelling it through the small gap between the impeller discs in very fine droplets. These are further broken up by the air blast as they emerge from the impeller, to provide an aerosol spray or fog, which is directed toward the material undergoing treatment.

It is frequently desirable to place the generator on the ground or other support, and direct it toward the target for operation over a considerable period of time. For this purpose, a hinge pin plate 165, having depending lugs 106, is secured to the bottom of the casing section 24, and the lugs are pierced to receive the ends of a supporting standard or bail 107. This standard is of generally triangular shape, as shown in Fig. 4, and may be formed readily by bending a length of rod. The lower apices 1438 may be covered with pieces of synthetic rubber tubing 199, to prevent marring a surface such as a table or counter top. One end 1311 of the bail is of the ordinary short bent shape, while the other end has a somewhat longer inwardly bent portion 112, which in turn is bent at right angles to provide a leg 113, and the end of the leg is again bent at right angles, and parallel to the portion 112, to form a foot 114-. By inspection of Figs. 1 and 2, it will be seen that the base of the standard may be placed on the supporting surface, with the foot 114 abutting the casing section 21, or the bail may be folded back against the casing section 2'7, in which case the leg 113 and foot 114 provide a low angle inclination.

It will accordingly be understood that the present invention provides an improved aerosol generator, wherein the liquid and motor casings may be readily fabricated from sheet metal and interconnected through an equally easily fabricated adapter section. The motor casing 21 may be readily d lfichi d from the adapter casing 24, in which event the shaft 51 either pulls out from the coupling 87, or pulls the coupling with it, depending upon the frictional grip between the joints. The motor 31 may also be withdrawn readily from the casing 21, and the impeller may likewise be removed without disturbing the motor. Irrprovements have also been made in the location of the motor control switch, the impeller, the coupling, and the supporting standard, the latter accommodating itself to deliver the aerosol at either low or high trajectories, and being self-locking in either position.

While the invention has been described with respect to a single embodiment, it is intended, of course, that there shall be encompassed within its scope all those variations and modifications which are covered by the following claims.

I claim:

1. An aerosol generator comprising a cylindrical motor casing having an open end and a closed end formed with an axial aperture, an adapter casing having an open end telescopingly engaging the closed end portion of the motor casing, said adapter casing having a wall at its opposite end, and a reservoir casing telescopingly engaging the adapter casing at said opposite end, a motor mounted in the motor casing in spaced relation to the Wall thereof, said motor having a shaft formed with an axial duct therein, an impeller mounted on one end of the motor shaft and having a periphery closely spaced with respect to the open end of the motor casing, a fan mounted on the motor shaft adjacent the closed end thereof, said adapter casing being formed with a plurality of circumferential apertures between the closed end of the motor casing and said wall of said adapter casing, whereby air may be admitted through the adapter casing apertures and the axial aperture of said motor casing for propulsion by said fan toward said impeller, a suction tube extending through the wall of the adapter casing into the reservoir casing, said suction tube being substantially in axial alignment with the motor shaft, a conduit and valve in the reservoir casing for supplying to said suction tube liquid adapted to be contained in the reservoir casing, and a shaft seal having an end positioned over the fan end of the motor shaft and another end over the adapter end of the suction tube, said seal having an internal hollow portion in fluid communication with the suction tube and duct of the motor shaft, whereby liquid adapted to be contained in the reservoir casing may flow to said impeller.

2. An aerosol generator comprising a casing having a motor driven impeller and a fan mounted therein, together with a reservoir for liquid adapted to be supplied to said impeller, and a standard connected to said casing for supporting said casing upon a surface at different angles, said casing having a hinge plate secured to the circumference thereof, said plate having depending lugs formed with apertures, a rod bent into a generally triangular formation having free ends pivotally mounted in said apertures, one of said ends being bent outwardly from the sides and base of said formation to provide a leg, said leg being bent substantially parallel to said formation to form a foot, said leg being of less length than the height of said formation, whereby said standard may be swung to support said casing either on the base of said formation or said foot.

References Cited in the file of this patent UNITED STATES PATENTS 1,506,226 Dick Aug. 26, 1924 1,879,675 Fitzgerald Sept. 27, 1932 1,930,539 Renshaw et a1 Oct. 17, 1933 2,151,100 Hadley Mar. 21, 1939 2,379,035 Phillips June 26, 1945 2,607,571 Hession Aug. 19, 1952 2,607,574 Hession Aug. 19, 1952 FOREIGN PATENTS 287,105 Great Britain July 12, 1928 

